1. Field of the Invention
The present invention relates to a porous ceramic scaffold having an organic/inorganic hybrid composite coating layer that includes a bioactive factor, as well as a method for production of the same. More particularly, the present invention relates to a porous ceramic scaffold for biomedical applications, uniformly coated with a hybrid composite that contains a bioactive factor and is formed of a high bioactivity silica xerogel and a physiologically active organic substance, as well as a method for manufacturing the same.
2. Description of the Related Art
As general medical operations to recover bone defects, autogenous and/or allogeneic bone graft methods have been employed since early times. However, autogenous bones are not provided in a sufficient amount to recover overall bone defects and have a problem of requiring secondary operation at a donor site. Allogeneic bones have disadvantages of causing infection or infectious diseases. Therefore, extensive research and development into bone graft materials using artificial materials with biostability but without worry about infections have recently been conducted.
As such materials, bio-inert (or bio-inactive) ceramic materials such as alumina, zirconia, etc., or bio-active ceramic materials such as hydroxyapatite, calcium phosphate based ceramics (that is, tricalcium phosphate (TCP), biphasic calcium phosphate (BCP)), etc., are broadly employed.
Specifically, in order to fabricate a scaffold similar to biological tissues, attempts to fabricate a scaffold having a pore structure have been implemented. It is known that such a pore structure enables tissue cells to be suitably adhered to a scaffold and may induce and accelerate regeneration of tissues. The foregoing method for fabrication of a porous structural scaffold may include, for example: a salt-leaching process that includes mixing ceramic molecules with insoluble particles such as salt in a solvent and casting the mixture, followed by removal of the solvent and particles to thereby form pores; a sponge-method that includes using a sponge material such as polyurethane foam, as a basic framework, injecting a ceramic slurry thereto to coat the framework, and removing the sponge through heat treatment, to thereby form a porous body; a freeze drying method that includes preparing a ceramic slurry in water and freeze-drying the slurry to form a porous body, or the like. Meanwhile, Korean Patent No. 879127, entitled “Method for controlling pores of porous material through freeze-casting and porous material manufactured by the same,” invented by the present inventors, discloses a process for manufacturing a porous ceramic scaffold through freeze-drying using camphene. According to this technique, porosity, pore size, pore arrangement, or the like may be easily controlled while maintaining an open pore structure of the porous material.
In order to induce rapid tissue regeneration in vivo, in addition to the attempts for improvement of structural materials described above, attempts to deliver a variety of body vitality factors (often referred to as ‘bioactive factors’) capable of directly inducing tissue regeneration as well as the material have recently been conducted. However, such a ceramic material principally needs heat treatment at a high temperature, thus entailing a limitation in delivering bioactive factors. There was an attempt to spray a solution containing bioactive factors over a porous scaffold to thereby deliver the bioactive factors adhered to a surface of the scaffold. However, such method has a difficulty in stably delivering the bioactive factors for a long time. Further, although studies into an improved porous scaffold having a coating layer formed of a biopolymer, in which bioactive factors are loaded, have currently been conducted, this method has also a limitation in controlling loading capacity and discharge capacity of the bioactive factors.